adaptive mechanisms for cytosolic sodium homeostasis
Kader, Md. Abdul
(2006).
Salt stress in rice.
Diss. (sammanfattning/summary)
Ultuna :
Sveriges lantbruksuniv.,
Acta Universitatis Agriculturae Sueciae, 1652-6880
; 2006:57
ISBN 91-576-7106-0
[Doctoral thesis]
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Abstract
This thesis concerns salt stress in plants, particularly sodium (Na+) stress. A high concentration of Na+ in the cytosol interferes with many K+-binding enzymes and thus, hinders the metabolic activities in cells and is termed as Na+ (ionic) toxicity. Two important aspects of Na+ toxicity in rice (Oryza sativa L. cvs. Pokkali and BRRI Dhan29) cells are described: i) how Na+ is transported into and out of cells, and ii) how cells react by changing cytosolic Ca2+ and pH for activation of the adaptive responses. Under salt stress the ability to reduce Na+-influx into the cytosol, and subsequently increase the compartmentalization of cytosolic Na+ into the vacuole, appeared to be the significant salt-tolerance determinant in the salt-tolerant rice cv. Pokkali. These mechanisms were either absent, or less efficient, in the salt-sensitive rice cv. BRRI Dhan29. A lower Na+-uptake in cv. Pokkali, compared to that in cv. BRRI Dhan29, depended on different types of transporters involved in these two cultivars. In cv. BRRI Dhan29 the transporters mediating Na+-influx were K+-selective channels and NSCCs, whereas NSCCs were the main pathways for Na+-uptake in cv. Pokkali. Apart from the lower Na+-uptake, cv. Pokkali seemed to take up Na+ only transiently and extrude it mainly into the vacuole. Moreover, to maintain a low cytosolic Na+/K+ ratio, Pokkali also might have increased K+-uptake under salt stress. The study indicates that Na+ must be sensed inside the cytosol, before any changes in cytosolic [Ca2+]cyt and [pH]cyt occur. Sensing of Na+ differentially induced [Ca2+]cyt and [pH]cyt changes in the two rice cultivars. Also, the sources for the changes of [Ca2+]cyt and [pH]cyt were different in the two rice cultivars. Internal stores in cells like vacuole and ER appeared to be the major sources for [Ca2+]cyt increase in cv. Pokkali, whereas the apoplast was more important in cv. BRRI Dhan29. The [pH]cyt was differentially shifted in the two rice cultivars, in response to salt stress, and was coupled to different H+-ATPases.
Authors/Creators: | Kader, Md. Abdul | ||||
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Title: | Salt stress in rice | ||||
Subtitle: | adaptive mechanisms for cytosolic sodium homeostasis | ||||
Year of publishing : | 2006 | ||||
Number: | 2006:57 | ||||
Number of Pages: | 44 | ||||
Papers/manuscripts: |
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Place of Publication: | Ultuna | ||||
ISBN for printed version: | 91-576-7106-0 | ||||
ISSN: | 1652-6880 | ||||
Language: | English | ||||
Publication Type: | Doctoral thesis | ||||
Full Text Status: | Public | ||||
Agrovoc terms: | oryza sativa, varieties, salts, osmotic stress, salt tolerance, soil salinity, sodium, toxicity, ions, soil transport processes, nutrient uptake, homeostasis, chemiluminescence method, microscopy | ||||
Keywords: | salt stress, Na+ toxicity, Pokkali, BRRI Dhan29, fluorescence microscopy, Na+ transport, confocal microscopy, Ca2+ and pH signaling | ||||
URN:NBN: | urn:nbn:se:slu:epsilon-1188 | ||||
Permanent URL: | http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-1188 | ||||
ID Code: | 1095 | ||||
Department: | (NL, NJ) > Dept. of Plant Biology and Forest Genetics (until 131231) | ||||
Deposited By: | Kader Md. Abdul | ||||
Deposited On: | 20 Sep 2006 00:00 | ||||
Metadata Last Modified: | 02 Dec 2014 10:09 |
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